Safety and Efficacy of Miglustat in Chinese NPC Patients

Inclusion Criteria: * Patients with confirmed 2 pathogenic mutations in either Niemann Pick Type C Gene 1 or 2 (NPC 1 or NPC 2) or 1 pathogenic mutation in either NPC1 or NPC2 plus a positive biomarker (oxysterol or lysosphingolipids or bile acids) plus high clinical suspicion * Signed informed consent prior to any study-mandated procedure. * For subjects who are younger than 18 years consent must be sought of at least one legal guardian who shall sign the informed consent form and indicate the relationship between him/her and the subject. * Subjects who are 18 years or older must sign the consent. If the subject cannot make an independent decision to participate in the study, consent must be sought of the legal agents who shall sign the informed consent form and indicate the relationship between him/her and the subject. * Male and female subjects aged 4 years and older. * Subjects who can performed the tests for the horizontal and vertical saccadic eye movements; * Subjects who are able to swallow the study drug; * Women of childbearing potential are only eligible if the following applies: * Negative urine pregnancy test at screening. * Agreement to undertake monthly urine pregnancy tests during the study and up to at least 30 days after study treatment discontinuation. * Agreement to use one of the methods of birth control / follow the contraception scheme from screening up to at least 30 days after study treatment discontinuation. * A fertile male (physiologically capable…